Sensitivity of MRI-guided near-infrared spectroscopy clinical breast exam data and its impact on diagnostic performance

Abstract

Abstract:In this study, data from breast MRI-guided near infrared spectroscopy (NIRS) exams delivered to 44 patients scheduled for surgical resection (ending in 16 benign and 28 malignant diagnoses) were analyzed using a spatial sensitivity metric to quantify the adequacy of the optical measurements for interrogating the tumor region of interest, as derived from the concurrent MRI scan. Along with positional sensitivity, the incorporation of spectral priors and the selection of an appropriate regularization parameter in the image reconstruction were considered, and found to influence the diagnostic accuracy of the recovered images. Once optimized, the MRI/NIRS data was able to differentiate the malignant from benign lesions through both total hemoglobin (p = 0.0037) and tissue optical index (p = 0.00019), but required the relative spatial sensitivity of the optical measurement data to each lesion to be above 1%. Spectral constraints implemented during the reconstruction were required to obtain statistically significant diagnostic information from images of H 2 O, lipids, and Tissue Optical Index (TOI). These results confirm the need for optical systems that have homogenous spatial coverage of the breast while still being able to accommodate the normal range of breast sizes. References and links1. P. Skaane, S. Hofvind, and A. Skjennald, "Randomized trial of screen-film versus full-field digital mammography with soft-copy reading in population-based screening program: follow-up and final results of Oslo II study," Radiology 244(3), 708-717 (2007 199-209 (2003).

MR-Guided Near-Infrared Spectral Tomography Increases Diagnostic Performance of Breast MRI

“…Some MRI/NIRST examinations (14 in total) were excluded from the analysis based on a quantitative and objective assessment of the optical signal sampling of the MRI contrast-enhancing ROIs, which we attribute to the incomplete breast coverage that occurs with the current version of the optical imaging breast interface used in this study (10). The optical signal cutoff used to define an evaluable MRI/NIRST examination was based on its measurement sensitivity to the contrast-enhancing ROI because the optical measurements did not adequately interrogate the ROI in every case.…”

“…Fourteen examinations were excluded from analysis because of insufficient coverage of the region of suspicion by the optical fiber array. Previous work (16, 18) has shown that optical image accuracy depends on having light signals that propagate through the abnormal region of interest with sufficient strength to be detected above the noise floor of the optical imaging array, and a measurement signal cutoff of 0.75% lesion sensitivity (relative to total sensitivity) was considered (10) as the minimum acceptable data sensitivity to the tissue region under evaluation. Based upon this analysis, data from 30 patient examinations met the signal sensitivity cutoff criterion, indicating that the breasts of these patients were accurately imaged across the plane of the tumor, and were subsequently evaluated.…”

“…In this study, 44 women with breast abnormalities of unknown diagnoses scheduled for surgical resection were imaged to estimate the diagnostic value of MR-guided NIRST when used to characterize suspicious regions identified by dynamic contrast-enhanced MRI (DCE-MRI). The multimodality breast examinations in 14 of these subjects yielded optical data that did not meet minimum lesion sensitivity criterion (10), and were excluded from the final analysis of the remaining 30 subjects. Abnormalities were characterized relative to the background breast as either malignant or benign, and scored versus the subsequent pathologic diagnosis.…”

Breast cancer detection using Ktrans MRI imaging to guide near infrared spectroscopy tomography

“…Detailed information about the instrumentation can be found in previous publications [1,4,5]. The device included six FD wavelengths (spanning from 660nm to 850nm) and three CW wavelengths (900nm to 950nm).…”

“…Near-Infrared Spectral Tomography (NIRST) has shown a good potential for breast cancer characterization [1][2][3][4][5]. The image reconstruction of NIRST is a typically ill-posed, ill-conditioned and nonlinear inverse problem because of the high degree of light scattering and a limited number of boundary measurements [6][7][8][9].…”